Due to the modern improvements of infant nutritional evaporated milk, an infant not only needs to be breast-fed, but also needs the infant nutritional evaporated milk to assist in the infant's growth. The common way of using evaporated milk is through bottle-feeding, i.e. place proper quantity of evaporated milk into a bottle with warm water, insert a nipple into a sealing-ring, and seal the sealing-ring to an opening of the bottle. When one shakes the bottle, the evaporated milk dissolves in warm water, and becomes ready for an infant to suck milk through a drawing hole on the nipple. Because the nipple covers the opening of the bottle, the only path to the inside of the bottle is through the drawing hole. When an infant sucks milk, the air inside the bottle is also being drawn out. Consequently, the air pressure in the bottle decreases. When the outer air pressure becomes much greater than the pressure in the bottle, the inner pressure is no longer sufficient to keep the nipple standing upwards for the infant to suck continuously. The infant has to repeatedly open his/her mouth to allow outer air to come in the bottle through the drawing hole in order to keep the air pressure inside the bottle high in order to suck out more milk. The above processes must be repeated until the infant finishes all the milk. Such interruptions are distracting to the infant and inconvenient for adults, who have to give the infant a constant hand in feeding.